The present invention relates to a lens drive apparatus for an optical pick-up apparatus, particularly relates to a lens drive apparatus having a compact structure, which is capable of including a micro motor apparatus for driving a collimator lens.
Optical pickup apparatuses, which are capable of recording and/or reproducing information onto/from optical discs, such as CD and DVD have been developed. Development of the optical pick-ups, which are capable of recording and/or reproducing information onto/from optical discs, such as Blu-ray Disc and HD DVD by using a blue violet semiconductor laser diode having a wavelength of 400 nm have rapidly proceeded. Here, with respect to an object lens in the optical pick-up apparatus for forming a focal light spot, a focusing operation for appropriately forming a focal light spot on the information recording surface of the optical pick-up apparatus and a tracking operation for appropriately following a track of the optical disc are required when recording and/or reproducing information onto/from the optical disc. Further, in response to the high speed recording and reproducing of DVD, which has been increasing in recent years, in addition to those operations, a tilt operation for conducting aberration correction by adjusting the tilt of the object lens has been increasing. In addition to this, in the case of HD and DVD, since the thickness of the substrate is relatively thick and the numerical aperture of the object lens has been increasing, accurately conducting the tilt operation becomes important subject. Thus, Unexamined Japanese Patent Application Publication No. 2006-190381 disclosed a miniature size actuator for conducting focusing, tracking and tilt controls of the object lens.
In many cases, a cantilever actuator is used in a slim type or an ultra slim type optical pickup apparatus, which is installed into a note type personal computer, in order to install the optical pick-up to a limited size while maintaining the limitation of a thickness direction. However, there is a problem that higher frequency resonance performance cannot be improved due to the structure of the actuator and the widening of the frequency characteristic of the actuator is difficult. Further, error sensitivity is extremely high and the performance extremely deteriorates on the vibration, shock and environmental changes when operating the actuator. Thus, a symmetrical type actuator, in which driving coils are symmetrically disposed against the object lens, is preferable. However, when adopting the symmetrical type actuator, it is difficult to reduce the size in the optical axis direction and the size of the apparatus becomes large. Further, there is a limitation in the size when disposing parts. Particularly, in the recent optical pick-up apparatus, which is compatible for three wavelengths, a collimator lens is arranged to move in the optical axis direction to correct spherical aberration and to optimize the aberration. When disposing the movable collimator lens adjacent to the object lens, since a micro motor for driving the collimator lens needs to be installed in the optical pick-up apparatus, there is a problem that the space adjacent to the object lens is limited. Further, in the case of the symmetrical type actuator, there is a possibility that an arm section for moving the collimator lens touches to a magnetic circuit section of the actuator.